Actually, Pacific Overtures only calls for male actors, except the very last song. (Until Japan 'modernizes', men play both roles)</SondheimFangirl>
Anyway, the big trouble with the 'colorblind' casting method is that it leaves movies really vulnerable to the subconscious racism that permeates our society on all levels. There's a really famous study done in the 60s and again more recently that asks little black girls to choose between blonde caucasian dolls and black dolls, and even today, the girls overwhelmingly choose the white dolls.
The point is, even when people say that they're casting regardless of race, they are still informed by the society they grew up in -- and right now, our society says, almost overwhelmingly, that white people are heroes, black people are subservient/supporting characters, and Asians are nerds. There are exceptions to this, of course, but these are the broad stereotypes that inform casting.
So this is why it's really disappointing that a show that cast dark-skinned people as heroes and light-skinned people as villains is being adapted into a movie where the reverse is true. It's not an unforgivable sin; after all, it's pretty typical. But the fact that it's typical is exactly what's wrong: what could have been a chance to shift those stereotypes a little bit just ends up reinforcing them.
(This is also exactly how you get a show like Firefly, set in a universe where Chinese is the dominant culture, but there are no Asians at all. Anywhere. Color-blind casting, hooray!)
Anyway on the positive side, given that the movie stands a good chance of flopping, at least Hollywood won't have yet another chance to say "it failed because it had a minority lead." (They can just blame Shyamalan instead!)
